Star Trek might count. The Pilot ''The Cage'' was rejected and they made ''Where no man has gone before''. The Cage was ''too cerebral'', and they were right that the ''Mom and Pops'' out in TV land. If Star Trek had stuck with the ''cerebral'' stuff, it likely would not have been a hit.

I think ''They'' forced poor Joss Wheaton to have a ''space hooker'' on Firefly...and really is a Great Character.